Scientist believe that about 20 to 25% of the universe is made of

The answer is Dark Matter.

Explanation:

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.